In this specification, where a document, act or item of knowledge is referred to or discussed, this reference or discussion is not an admission that the document, act or item of knowledge or any combination thereof was at the priority date part of common general knowledge, or known to be relevant to an attempt to solve any problem with which this specification is concerned.
The creative industries, such as those involved in film, television program and advertisement production, and in the broadcast of live events, operate on a basic proposition that holders of rights in the relevant content are remunerated for the use of that content. This promise of (sometimes very lucrative) remuneration provides an incentive to producers to undertake substantial financial risks involved in the creation of such content. In the traditional distribution chain, rights holders receive remuneration through means such as ticket sales, physical media sales and rentals, advertising revenue and subscription fees.
Internet connection speeds are continually improving as broadband networks are deployed, and it is now becoming feasible to use the Internet as a content distribution medium. However, whilst it may be technically feasible to distribute content such as film and television programs and live event broadcasts over the Internet, commercial considerations associated with protecting rights holders against unauthorised use of their content and thereby providing proper remuneration, are yet to be adequately resolved.
Content may be transferred over the Internet either by downloading or streaming. Downloading involves the transfer of an entire file to a device for subsequent viewing by means of pre-installed playing software, such as the Windows Media Player or Apple's Quicktime, whereas streaming involves the simultaneous downloading and playing of a file, with the playing software commencing play as soon as it has downloaded sufficient data to do so.
The key advantage of streaming over downloading is that a user need not wait for the complete download of a large file (a process which may take some time) before commencing a playback session. Downloading is thus generally unsuitable to Internet broadcasts of live events in real time or close to real time, which can only be implemented by way of content streaming.
Applicant's previous International Patent Application WO-03/005190, the contents of which are hereby incorporated by reference, describes a system and method for content playback using a player which is not saved to the user's machine and which can be effected without reference to the operating system registry. The invention can be applied to both streamed content and saved content (eg. content on a physical medium).
Generally, when streaming is adopted, eg. to broadcast a live event on a pay-per-view basis, vulnerabilities in current streaming software packages can leave open the possibility of unauthorised use of the streamed content. One such vulnerability, known as playback control circumvention, involves an attacker stripping or modifying content entitlements to gain unauthorised access to the content. This enables an unauthorised user to access content and to possibly redistribute the illegally accessed content, thereby denying the rights holder of due compensation.
Another mode of attack involves a user making an exact copy of a specific instance of a media player, enabling the user to violate replay limitations.
A further weakness in current web streaming system enables users to steal or reuse a specific session ID allowing them to view the content more often than intended by the rights holder.
It would be advantageous to provide a web streaming system which is less vulnerable to attack through one or more of these modes than the systems which are currently available.